Respirator with interchangeable filters



Feb. 9, 1954 R. B. EVANS 2,668,532

RESPIRATOR WITH INTERCHANGEABLE FILTERS Filed April 4, 1951 Patented Feb. 9, 1954 RESPIRATOR "WITH INTERCHANGEABLE F ILT-ERS .BohertB. Evans, Plum Township, Pa., assignor to Mine Safety Appliances Company, Pittsburgh, Pa., a corporation of Pennsylvania Application April 4, 1951, Serial No. 219,274

8 Claims.

This invention relates to respirators, and more particularly to one inwh-ich different types of air filters can'readily be attached 'to the face-piece by the wearer.

.It'isamongtheobjectsofthis invention to provide a respirator which can be used in either a dust-laden or a noxious gas atmosphere, which has a. face-piece that can be-providedwith readily interchangeable ifilters of difierent types, which permits the wearer to quickly change from one type of filter to another, and in which the filter can not be removedaccidentally from the facepiece.

:Inaccordance with this invention, a face-piece has its air inlet opening-aligned with an outlet opening in the wall of an air filter. Removable tubular means extend through both openings and form-a sealwith ,the'adjoining walls'of the facepieceand filter. Removable means is provided for normally holding .the tubular means in position. In one form, aitube extends throughboth openings in sealing engagementxwith their sides, and .the ends of :the tube .are connected to the filter .and face-piece to "normally hold them together. The tuberis'removablefrom at least one of :the openings topermit the;filter to be disconnected fromithe 'face piece. The tube preferably has 'Ifianges at its Lends :and is .fiexible, but removable'means is insertedinithe tube to normally hold it in place. This removable means most suitably is a rigiditube-which may :form part of an inhalation valve.

The preferred embodimentiof the invention is illustrated in the accompanying drawings, in which Fig. l-is a side view of my respirator partly broken away :to show in section the :connection between a gas or vapor filter and the face-piece; Fig. '2 Ba rear or-inside view-of the face-piece; Fig, 3 is a front view-of the face-piece with the filter removed; Fig. '4 is'a rear view of thefilter; *Fig. -5 is an enlarged end view of the connecting "grommet in its original form; and Fig. 6 'is a rear view, partly broken-away, ofanother type of filter which can replace the one shown in Fig. 4.

Referring tothe drawings,- a"face-"piece is shown which has'a cup-like'body l adapted to fit over the nose and mouth. The edge of "the cup -is-'contoure'd tothe shape of the 'face'and is coveredby a resilient sealing'member'z that forms a cushion andseal against the face. The facepiece can be held inpla-ce by the usual strap 3 around the head. The front of the face-piece is provided with an air inlet opening 4 of any suitable shapejtheone shown being more or less elliptical. Although it is possible for the wearer to exhale betweentheface-piece"cushion and his face, .itZislp-referred to provide the lower'part of :tlie .cupflwithronerormore outlets. 5 (Fig.2) covered .byzflexible exhalation valve discs i5 thatclose '.;the outlets whenthe.wearer'inhales.

Disposed in front of the face-piece is .anair filter 8 which may have any suitable shape and may be designed for filtering out particulatematter or noxious gaseous material. Theoneshown in Fig. l is provided interiorly with abody of any suitable material 8 that will filter out the nude sired noxious gases by chemical reaction with them. This air filtering or purifying material is spaced from the back wall 10 of .the filter :byan interior perforated partition 1,]. The rear wall of the filter is provided with an outlet opening l2 (Fig. 4) for alignment with the inlet opening 4 of the face-piece. Preferably, the two openings have substantially the same shape and size.

It is a feature of this invention that the filter and the face-piece are connected together in such a manner that the wearer caneasily-separate them and replace the filter byanother -.one of the sameor a diiferentkind. Accordingly,;a very short removable tube is provided that extends through both openingsA and l2 in sealing engagement with the adjoining wallsof-the .facepiece and filter which it detachably conneotstogether. Preferably, the tube is formed from a. flexible grommet .14 of rubber-like material-and originally of circular form, suchas shown in -E'ig. 5. The diameter of the grommet issuch that when it is deformed into the shape of the registering openings in the race-piece and filter the central portion of the grommet between its-end flanges will fit against the sidesof *thoseropenings. The length of the grommet is :suCh :that when it extends through the two-aligned-openings with the filter and face-'piece-in engagement with each other, the-end fiangesof the grommet will overlie and engage the inner surfacesiofithe front and rear walls of'the face-pieceandfilter,

respectively. The grommet flanges thus :hold-the filter and face-piece-together, and the grommet as a whole formsan air passageleading-fromthe filter into the face-piece.

To prevent the filter from accidentally being disconnected from the face-piece and to insure a good seal between them and-thegrommet-so that unpurified air-can not leak-into=the facepiece around the grommet the grommet expanded into tight engagement with the-sides-of the two openings rand-I12. '-As longras-itis thus expanded it can not be collapsed or compressed and removed from either opening. The expansion preferably ispmducedby-a rigid tube I5 that is slightly larger-.thanvthe inside-of the grommet andis pushedinto itfrom its face-piece end. When it is desired todisconnect thefilter from the face-piece, this rigid .tubefirst ispulled out of the grommet so that'the grommetflanges can be compressed or deformed to ,permit them to be pulled through one orboth of'the aligned openings. The outer end of tube 1515 surrounded by a flange I 6 to providea gripjfor pulling the tube out of'the grommet -and ,also:to

provide a support for a headed pin I! on which a flexible flap valve I8 is hung. This valve ex tends across the tube and closes it when the wearer exhales, thereby closing the air inlet passage. In this Way an inhalation valve is formed and is combined with the connection between the filter and the face-piece.

When the filtering material in the filter starts to become inactive, the filter can readily be removed from the face-piece and replaced by another like it, or, if it becomes necessary to use the respirator in a dust-laden atmosphere, the filter can be replaced by a mechanical dust filter. Such a filter is shown in Fig. 6. It is formed from a suitable case 20 containing a sheet 2| of any well-known dust-filtering material clamped in place by a perforated cover 22. The rear wall of the case is provided with an air outlet 23 like the one in the other filter. The filter can be connected to the face-piece by holding the two together and then inserting grommet I4 in the two aligned openings 4 and 23. After the grommet flanges spring out against the inner surfaces of the adjoining walls, the inhalation valve tube [5 is inserted in the grommet to lock it in place.

The invention disclosed herein makes it possible to use the same face-piece with different types of filters. It reqLires only a few moments to change from one filter to another. The inhalation valve serves the additional functions of locking the connecting grommet in place and insuring a seal between it and the sides of the registering openings in the filter and face-piece. Ihe connection between the two is simple and inexpensive.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A respirator comprising a face-piece provided in its wall with an air inlet opening, an air filter provided in its wall with an air outlet opening aligned with said inlet, a flexible grommet extending through both openings and having end flanges normally overlying the inner surfaces of said walls to detachably connect the face-piece and filter together, the outside of the grommet between said flanges tightly engaging the sides of said openings so that the grommet forms a sealed air passage connecting the filter with the face-piece, and a rigid tube removably inserted in the grommet to prevent it from being collapsed and withdrawn from either of said openings.

2. A respirator comprising a face-piece provided in its wall with an air inlet opening, an air filter provided in its wall with an air outlet opening aligned with said inlet, a flexible grommet extending through both openings and having end flanges normally overlying the inner surfaces of said walls to detachably connect the face-piece and filter together, and a removable rigid tube inserted in the grommet and being of a diameter to expand the grommet tightly against the sides of said openings.

3. A respirator comprising a face-piece provided in its wall with an air inlet opening, an air filter provided in its wall with an air outlet opening aligned with said inlet, a flexibl g om- 4 met extending through both openings and having end flanges normally overlying the inner surfaces of said walls to detachably connect the face-piece and filter together, the outside of the grommet between said flanges tightly engaging the walls of said openings so that the grommet forms a sealed air passage connecting the filter with the face-piece, a rigid tubular member inserted in the grommet in frictional engagement therewith, and a valve member carried by said tubular member for closing it during exhalation.

4. A respirator comprising a face-piece provided in its wall with an air inlet opening, an air filter provided in its wall with an air outlet open-- ing aligned with said inlet, a flexible grommet extending through both openings and having end? flanges normally overlying the inner surfaces of said walls to detachably connect the face-piece and filter together, a tubular valve member in-- serted in the grommet in frictional engagement therewith and having a diameter great enough to expand the grommet into sealing engagement with the sides of said openings, and a flap valve mounted on the face-piece end of said tubular member for closing it during exhalation.

5. A device for connecting the outlet of an air filter with the air inlet of a respirator face-piece, comprising a flexible grommet adapted to extend through both openings, a tubular inhalation valve member for insertion in the grommet to expand it into sealing engagement with the sides of said openings, and a valve closure member supported by said tubular valve member for closing the tubular member during exhalation.

6. In a respirator, a flexible grommet adapted to extend through aligned openings in adjoining walls of a face-piece and air filter and having integral end flanges for normally engaging the inner surfaces of said walls to detachably connect the face-piece and filter together, the outside of the grommet between said flanges being adapted to tightly engage the sides of said openings so that the grommet will form a sealed air passage connecting the filter with the face-piece, and means removably inserted in the grommet adapted to hold said flanges beside the inner surfaces of said walls.

7. In a respirator, a flexible grommet adapted to extend through aligned openings in adjoining walls of a face-piece and air filter and having end flanges for normally engaging the inner surfaces of said walls to detachably connect the face-piece and filter together, and a removable rigid tube inserted in the grommet and being of a diameter to expand the grommet tightly against the sides of said openings.

8. In a respirator, an expandable tube for extending through aligned openings in adjoining walls of a face-piece and air filter, the tube being adapted to fit against the sides of these openings in sealing engagement therewith, and removable tubular means inserted in the tube to normally hold said tube in position.

ROBERT B. EVANS.

References Cited in the file of this patent UNITED STATES PATENTS 

